In the background of the manufacture and development of electronic circuitry using printed circuit boards, many and varied methods and configurations have appeared in an effort to improve such printed circuit boards, and to reduce the overall cost of manufacture. A diligent search of the prior art reveals several concepts which in some ways appear to be somewhat similar to the present invention. In the present invention, a method of automated machine insertion of certain circuit components is disclosed.
U.S. Pat. No. 4,109,296 by Rostek describes an insertable component for machine insertion into a printed circuit board. Flow soldering is then normally used to provide an electrical bond between the board conductors and the component contacts. The sides of the component carrier are straight and fit into a straight sided hole in the printed circuit board and the solder prevents dislodgement. In the present invention, the concept is to provide a solderless connection between the inserted component carrier and the printed circuit board, thus eliminating the soldering operation and also the subsequent cleaning operation to remove flux. Also by using a solderless method, unintentional solder-bridging is avoided.
Another important difference found in the present invention, is that the component carrier is connected with conductive epoxy and is press fitted into a corresponding hole in the printed circuit board. In this manner, a tightly wedged fit is obtained, providing a firm and positive electrical connection between the component carrier and the conductive leads of the printed board.
U.S. Pat. No. 3,192,307 by Lazar teaches a method of inserting a component carrier into a hole in a printed circuit board, using manual means for insertion, the component carrier and the receiving hole having straight sides, the component carrier having tabs for surface contact with printed contacts on the outside surface of the printed circuit board and held in contact by the use of adhesive sheeting. In contrast, the present invention provides that the chip carriers are press fitted into a mating hole or elongated slot formed in the printed circuit board and are held in place further by the contact with the aluminum heat sink plates on both sides as well as the "J" lead connections, which eliminates the use of adhesive sheeting.
U.S. Pat. No. 3,351,816 by Sear, et al. teaches the use of a heat conducting aluminum plate, however, this aluminum plate actually is a type of circuit board serving the dual function of printed circuit board and heat sink, a series of such boards being bonded together. Being bonded together, such printed circuit boards are not readily removed from each other for repair or replacement as is found in the present invention. Further, this concept does not include provision for a combined optical buss.
U.S. Pat. No. 2,963,538 by Dahlgren teaches the use of glass fibers in a flat cable. The use of such glass fibers by Dahlgren is for the purpose of providing strength to the cable and does not anticipate the use of glass fibers for the transmission of data by optical fiber in combination with a printed circuit board.
U.S. Pat. No. 3,366,914 discloses an insertable solderless connector with a concept quite different to that of the present invention. This patent illustrates a two-piece connector, having a flange to engage one side of a printed circuit board and a compressible lip to engage the opposite side after insertion through a hole in the printed circuit board. This device appears to be intended for manual insertion as the specification recites a necessity to trim off projecting contact ends after insertion. The present invention provides a one piece chip carrier which is held securely by the contact with the heat sink plates, using no flanges, and requiring no trimming.
U.S. Pat. No. 3,365,620 by Butler, et al. teaches a multi-layered printed circuit board system that embodies an internal cooling system, however, unlike the present invention, the Butler patent discloses a liquid cooling system.
U.S. Pat. No. 3,133,773 by Ecker illustrates a configuration which, at first glance, resembles the present invention in regard to the glass fiber optical cables imbedded in the interior of the printed circuit board. Further reading of the Ecker patent discloses that the conductors imbedded in the material of the circuit board are of insulated copper wire and do not relate to the fiber optic system embodied in the present invention.
Accordingly, it becomcs apparent that the combination of features found in the present invention are not found in the references cited from the prior art, and that the present invention presents a novel and valuable departure from the prior art, as will be further demonstrated in the detailed description that follows.